1. Field of the Invention
The present invention relates to image data processing using optical character recognition for recognizing a character image in a document.
2. Description of Prior Art
In a digital copying machine or the like, digital image data may be subjected to various data processing. For example, when an image data obtained by reading a document is enlarged, the image data is subjected to interpolation in correspondence to the magnification. When the image is reduced, the image data are thinned in correspondence to the magnification.
However, in a copy obtained by the above-mentioned enlargement where the image data is interpolated simply, the outline of a character image may become disordered (or the outline may become jaggy), and in a copy obtained by the above-mentioned reduction where the image data is thinned simply, characters may be deformed. When a copy are read, characters in the copy are liable to be read with a strange feeling or not to be read due to such deterioration of image quality of enlarged or reduced characters.
On the other hand, in a prior art copying machine or the like, there is a saving mode wherein the number of copies of documents is decreased relative to the number of the documents. A saving mode includes reduction of digital image data obtained by reading documents. For example, in N-in-1 mode, as one of the saving modes, images of N documents are reduced and arranged in a layout, wherein N denotes a natural number, and the images in the layout are formed in a sheet of paper.
However, in prior art N-in-1 mode, an entire original document including a margin thereof is subjected to the reduction. For example, when two documents are reduced to a sheet of paper, the margin of the two documents is reproduced at the periphery of a sheet of paper (refer to an example in 2-in-1 mode shown in FIG. 15B). Then, the documents are reduced more than necessity, and this makes characters in the document smaller. Further, an output copy of portrait documents may be changed to a landscape output image. In such a case, portrait and landscape copies are mixed, and this is inconvenient for filing. Further, because a plurality of documents are reduced simply in a layout in a sheet of paper, when a copy is read, it is necessary to read the output images while confirming the order of the pages of the documents.